Archives de catégorie : biology+acidification

The End Of The Ocean Acidification Scare For Corals

by McCulloch et al., 2017, October 2017,  in co2science

Paper Reviewed: McCulloch, M.T., D’Olivo, J.P., Falter, J., Holcomb, M. and Trotter, J.A. 2017. Coral calcification in a changing world and the interactive dynamics of pH and DIC upregulation. Nature Communications 8: 15686, DOI:10.1038/ncomms15686

(…) The implications of the above findings are enormous, for they reveal that “pHcf upregulation occurs largely independent of changes in seawater carbonate chemistry, and hence ocean acidification,” demonstrating “the ability of the coral to ‘control’ what is arguably one of its most fundamental physiological processes, the growth of its skeleton within which it lives.

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Catastrophic’ sea level rise in the past may have drowned corals in Hawaii

by University of Sydney, September 28, 2017 in WUWT

Recent findings suggest that episodes of very rapid sea-level rise of about 20m in less than 500 years occurred in the last deglaciation, caused by periods of catastrophic ice-sheet collapse as the Earth warmed after the last ice age about 20,000 years ago.

Lead author, PhD candidate at the University of Sydney, Kelsey Sanborn, has shown this sea-level rise event was associated with “drowning” or death of coral reefs in Hawaii.

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The Impact of Elevated CO2 on a Widespread Ectomycorrhizal Fungi

by McCormack et al., 2017, September 18, 2017 in FungalEcology

In light of the above findings, it would appear that, given the near-global distribution of this EM fungi and its importance in stimulating ecosystem productivity, the positive impact of elevated CO2 on C. geophilumproduction (~50% increase for a 200 ppm rise) represents a welcomed benefit for the future of Earth’s forests.

Study: plants are globally getting more efficient thanks to rising carbon dioxide

by University of California, September 12, 2017 in WUWT

A trend toward greater discrimination under higher CO2 levels is broadly consistent with tree ring studies over the past century, with field and chamber experiments, and with geological records of C3 plants at times of altered atmospheric CO2, but increasing discrimination has not previously been included in studies of long-term atmospheric 13C/12C measurements. We further show that the inferred discrimination increase of 0.014 ± 0.007‰ ppm−1 is largely explained by photorespiratory and mesophyll effects.

In times of climate change: What a lake’s color can tell about its condition

by Forschungsverbund Berlin e.V. (FVB), September 21, in ScienceDaily

With the help of satellite observations from 188 lakes worldwide, scientists have shown that the warming of large lakes amplifies their color. Lakes which are green due to their high phytoplankton content tend to become greener in warm years as phytoplankton content increases. Clear, blue lakes with little phytoplankton, on the other hand, tend to become even bluer in warm years caused by declines in phytoplankton. Thus, contrary to previous assumptions, the warming of lakes tends to amplify their richness or poverty of phytoplankton.

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Prof Peter Ridd: the Great Barrier Reef recovers, our science institutions are failing us, science needs to be checked

by Alan Jones, interviews peter Ridd, July 28,  2017 in JoNova

Corals have a little thermometer built in them, when you take a core of them from many years ago we know what the temperature of the water was back when Captain Cook sailed up the coast, it was actually about the same temperature then. It was colder 100 years ago, but it has recovered from that. The temperatures on the reef are not even significantly warmer than average on a hundred year timescale.

Corals that bleach in one year will be less susceptible to bleaching in following years

‘Perfect storm’ led to 2016 Great Barrier Reef bleaching

by James Cook University and Université Catholique de Louvain, July 3, 2017, in ScienceDaily

Professor Wolanski said the study was subjective to the extent that there was a lack of oceanographic field data in the Great Barrier Reef itself for the 2016 el Nino event. By contrast, the amount of oceanographic field data in the Torres Strait and the northern Coral Sea was very good.

« What we presented is our best-informed attempt to reveal the mechanisms involved in causing the event, based on the available oceanographic data combined with the existing body of knowledge on the water circulation in and around the Torres Strait/Northern Great Barrier Reef region. »

Indirect Positive Effects of Ocean Acidification Can Overpower Sometimes Observed Direct Negative Effects

by S.D. Connell et al., 2017 in Current Biology (in CO2 Science)

The increasing absorption of CO2 and associated decline in seawater pH values is thought to pose direct harm to marine life in the decades and centuries to come by affecting rates of survival, calcification, growth, development and/or reproduction. However, as ever more pertinent evidence accumulates, a much more optimistic viewpoint is emerging.